Plug having a tool insert opening with a non-circular constant diameter cross-section



FIG. 1 is a perspective view of the plug.

FIG. 2 is a top view of the plug; and,

FIG. 3 is a side view of the plug.

The dotted line drawing portions are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a plug having a tool insert opening with a non-circular constant diameter cross-section, as shown and described. 